1. Field of the Invention
The invention relates to a control lever assembly for controlling two inter-related functions, and is particularly adapted for, but not limited to, controlling a throttle and clutch/gearbox unit of a marine power unit.
2. Prior Art
Marine control assemblies for controlling a marine clutch/gearbox unit and engine have been used for many years and, to avoid damage to the engine and gearbox, it is common to provide an interlock of some type. The interlock permits changing gears only when the engine is at idle, and permits acceleration of the engine only when the gearbox is fully engaged in either forward or reverse, or is in neutral. Such devices are shown in U.S. Pat. No. 3,382,737 and No. 4,160,499 issued to Manzolillo and Baba respectively. Whilst such devices are suitable in some applications, they tend to be relatively complex and thus relatively costly to produce and maintain. Furthermore, it is considered desirable to provide for the clutch lever a resilient "feel" relating to engagement of neutral, forward and reverse gear positions, and neither of these patents disclose devices which would serve concurrently as an interlock and yet provide this feel for all three clutch lever positions. Resilient feel improves feedback for the operator so that the operator knows when the appropriate gear or neutral is engaged. The clutch lever is considered to be the primary lever for control as it controls direction of the vessel and thus positive and accurate clutch lever location is important. A partially engaged gear resulting from inaccurate location of the clutch lever in a prior art device would prevent operation of the throttle due to the interlock and this could present difficulties when docking the vessel. In particular, if the gear in a prior art device were only partially engaged, a strong operator applying large forces to the throttle lever could, in some instances, override the clutch/throttle interlock by deforming the interlock structure with excessive forces, and thus accelerate the engine possibly at an inappropriate time, with resulting damage to the vessel, gearbox, clutch and/or engine.